Influence of Unit Cell Parameters of Tetrachiral Mechanical Metamaterial on Its Effective Properties

Metamaterials are of great interest due to their unusual properties and promising practical application. In the paper, we study a mechanical metamaterial bar composed of 81 unit cells. The unit cell is shaped as a cube with a two-dimensional tetrachiral base consisting of a ring and four ribs. Elastic deformation of a metamaterial specimen is numerically modeled in uniaxial compression and tension. The manner, in which the twist angle and support force at the fixed end of the metamaterial specimen depend on the structural parameters of the unit cell, is demonstrated. The dependence of the support force on the cell thickness is the only one showing a linear behavior. The cell parameters that have the greatest and least influence on the metamaterial twist angle and support force are determined. Value ranges of the parameters in which the twist angle is largely affected, are found.